Wednesday, July 17, 2013

July 17, 2013 - Week 4: Last week of class

This week was relatively short in terms of class time and field work, in fact we only went out to the field in one occasion. On Monday we had a short review of fluvial deposits and an introduction to deep-water deposits. We also discussed the similarities and differences between river, turbidite, debris flows, and hyperpycnal flow channels since they may look somewhat similar in map view but in detail they could be quite different. This reflects the differences in depositional environments and sediment sources.

View of Honaskogdalen, most of the lower areas are covered by moss or grass since the snow has melted but in some higher areas there are still patches of snow.  

Walking on rock fall and debris flows on the slopes of Honaskogdalen.

During our only day out in the field we visited Honaskogdalen, a fjord valley located about 7 km north of Longyearbyen. The walk to the outcrop area was long; it took us over an hour of walking to reach the outcrops we were studying. I was surprised to see that there was still snow in some of the channels and ravines, since it is July, but evidently much less snow than there was during our first day out in the field. Again we were divided into groups and given a certain area to map and create a stratigraphic column, and then we had to correlate our columns to interpret the depositional environment. The formation of interest is called Helvetiafjellet from the lower Cretaceous and consists of fluvial, deltaic, and tidal deposits representing an overall transgressive pattern. We were advised by our instructor to take pictures of the whole area and pinpoint in our drawings where we did the stratigraphic columns because correlating could be difficult after leaving the study area. The next day we realized she was right.

Wednesday was a short seminar day. The main goal for the day was to correlate all the stratigraphic columns and discuss our observations in the field.  The groups found coal seams, mud drapes, thick massive sandstone bodies, ripples, and dunes as well as parallel bedding. All of these agree with the environment of deposition expected but our main problem was agreeing on the correlation of our columns. Something we agreed on was the presence of several channels, which may explain why the deposits are different even if they are close to one another. Thursday was “reading day”, which we used to study for our final (comprehensive) exam on Friday.
Students at Sukkertoppen hill next to Longyearbyen, for a last hike together(me in the red jacket and jeans).

View from Sukkertoppen hill. Student dorms and Longyear glacier.
View of Longyearbyen from Sukkertoppen hill, UNIS is the marroon building in the center. Notice the brown sediment plumes coming from rivers draining glaciers and going into the blue fjord water.
Longyearbyen street, going from the sea towards Longyear glacier (on the background).

And just like any other class, this one also came to an end. I believe it was very rewarding, both academically and personally. I have gained perspective and experience on glaciated environments, which will be very useful since I live in the sub-tropics. Above all, the professors and fellow classmates were especially amazing and I am so grateful to have met them. 


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